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You have two general options when you need to use a hydraulic cylinder as part of your hydraulic system: single-acting or double-acting hydraulic cylinders. Both types are able to handle high-powered work to lift, move, pull, press, or complete other desired tasks.

To help you decide whether you need a double-acting or single-acting hydraulic cylinder, it is best to learn more about both types of cylinders, their functions, and what applications they are best suited for.
 

What Is a Single-Acting Hydraulic Cylinder?

A single-acting hydraulic cylinder has a single inlet connection for the hydraulic fluid. As the fluid flows into the cylinder, it pushes the cylinder piston rod to extend outwards in a single direction. Once the fluid flow stops the cylinder stops extending, when the valve operating the cylinder is reversed, a spring or gravity causes the piston to retract.
 
For example, the arms on a construction front loader could use a single-acting hydraulic cylinder to lift and raise the bucket on the front of the vehicle.  When the line to the cylinder is opened to tank gravity, along with the weight of the bucket and its contents, will cause the piston inside the cylinders on the loader arms to retract and lower back down to the ground.
 

What Is a Double-Acting Hydraulic Cylinder?

A double-acting hydraulic cylinder has dual inlet connections for the hydraulic fluid. Just like a single-acting hydraulic cylinder, one inlet will allow fluid to flow into the cylinder to extend the piston rod outwards to perform the designed work.
 
However, instead of relying on a spring or gravity to cause the piston to retract, hydraulic fluid is used. So, first, the fluid to the piston extension inlet is stopped. Then, hydraulic fluid is pumped into the second inlet on the other end of the cylinder to cause the piston rod to retract. As it does, the hydraulic fluid behind it is pushed back out through the inlet.
 
Double-acting hydraulic cylinders provide a bit more flexibility when controlling piston extension and retraction. It is easy to move the piston back and forth and ensure the plunger can be fully retracted to its original position.
 
In addition, work can be performed with double-acting cylinders somewhat faster since you do not have to wait for gravity or a spring to retract the piston.
 

Double-Acting vs. Single-Acting Hydraulic Cylinders

Aside from how the piston rod is operated and having one or two hydraulic fluid inlets, there are some other differences between double-acting and single-acting hydraulic cylinders you need to know. By understanding these differences, it can help you choose the right hydraulic cylinder to meet your objectives.
 

Double-Acting Cylinder Benefits

Some of the benefits you can gain when you use double-acting cylinders include:

• You can utilise both push and pull hydraulics.
• You can perform repetitive actions easier.
• They allow for faster retraction.
• They provide more precise control of the and desired functioning.

 

Single-Acting Cylinder Benefits

Using single-acting hydraulic cylinders in your equipment provides these benefits:

• They are easier to maintain than .
• They have simplistic designs since just needs to extend the piston.
• Cost-wise, single-acting cylinders are more economical when they can be used.
• Only a single inlet hose is required.

 

Double-Acting Cylinder Drawbacks

There are also some drawbacks to double-acting cylinders, such as:

• Depending on the hydraulic system and applications, you could require at least a 2-way valve.
• Each hydraulic cylinder will require two different hose connections.
• Performing maintenance on is a bit more complex.

 

Single-Acting Cylinder Drawbacks

Some of the drawbacks to using single-acting hydraulic cylinders are:

• There’s less precision and control over the movement of the .
• The piston just moves in one direction, and you have to wait for the spring or gravity to do its work to retract it.
• The springs used inside the cylinder do wear out from repeated usage. So, the piston will stop retracting when they do.

 

Key Applications of a Double-Acting Hydraulic Cylinder

Now that you have a better understanding of how double-acting hydraulic cylinders work and their pros and cons, let’s look at some of the key applications of using this type of cylinder for various applications.
 
For starters, double-acting cylinders are perfect for applications that require pressing, such as imprinting. The top pressure plates usually require the cylinder to be installed upside down. As such, the cylinders on the top pressure plate would not retract using a spring or gravity found in a single-acting cylinder.
 
Next, double-acting cylinders are well-suited for repetitive applications that need to be performed frequently—for example opening and shutting gates or doors.   Operating the digger arms on backhoes or excavators.
 
Third, double-acting cylinders are better suited if you require a delayed or controlled reaction time as part of your hydraulic system functioning. Most importantly, if you desire the flexibility of pushing and pulling hydraulic operations, you will want to use double-acting cylinders.
 

Key Applications of a Single-Acting Hydraulic Cylinder

Single-acting hydraulic cylinders have their useful purposes, too. They are a good choice for generalised lifting applications where springs or gravity can be used to retract the piston rod.
 
Another application for single-acting cylinders is whenever you do not require fast retraction and the cylinder is not being installed upside down. For instance, a hydraulic vehicle jack in a car service centre could use a single-acting hydraulic cylinder and rely on the weight of the vehicle to gradually cause the piston to retract.
 
In addition, single-acting cylinders are well-suited for a wide range of light commercial and industrial applications that require basic lifting or pushing movements. For example, some trash compactors use a single-acting hydraulic cylinder to compact the trash and a spring to retract the piston. 
 

What to Look For When Purchasing a Single-Acting or Double-Acting Hydraulic Cylinder

When choosing single-acting or double-acting hydraulic cylinders for your hydraulic system, you need to make sure that cylinders will perform the desired work and functions. It does not make any sense to invest in a single-acting cylinder when it will not perform the required work. Nor does it make sense to invest in a double-acting cylinder when a single-acting cylinder will meet your needs.
 
For example, if you need to move whatever is connected to the cylinders in two directions, then a double-acting cylinder is best. On the other hand, if you need to move the piston rod in a single direction and can rely on gravity or a spring for retraction, then a single-acting cylinder would be a good choice.

Next, you do need to consider the system design and what other hydraulic parts and components you will need. For example, with double-acting system designs, you need to remember to include the costs of installing 2-, 3-, or 4-way valve controls and pumps. Furthermore, you will need to run two hoses to each cylinder.
 
In addition, some system designs could use a combination of single-acting and double-acting cylinders depending on the system’s functions and applications. Last, you want to choose hydraulic cylinders that are built with high-quality parts and components that meet industry standards.
 

High-Quality Single-Acting and Double-Acting Hydraulic Cylinders

You can find the high-quality single-acting and double-acting hydraulic cylinders for every industry at White House Products, Ltd. Whether you need a single-acting cylinder for a light construction vehicle or double-acting cylinders for heavy industrial manufacturing purposes, we have or can make to your specification the cylinders you need.
 
We are also happy to help you choose which cylinders are best for your applications, as well as assist you with new hydraulic system designs. For further information, to request a free quote, or to order the cylinders you need, please feel free to contact us at +44 (0) 1475 742500 today!